Thyroid Hormone Replacement Therapy

What is thyroid hormone replacement therapy?

Thyroid hormone therapy is the use of manmade thyroid hormones to raise abnormally
low levels of natural thyroid hormones in the body. Thyroid hormone is usually given
in pill form and is often used to treat an underactive thyroid that is secreting little
or no thyroid hormones. The most commonly prescribed thyroid hormone replacement is
pure synthetic thyroxine (T4).

Who needs thyroid hormone replacement therapy?

Thyroid hormone therapy is generally prescribed when your thyroid is not making enough
thyroid hormone naturally. This is a condition referred to as hypothyroidism. Other
reasons for using thyroid hormone therapy may rarely include:

To control the growth of the enlarged thyroid gland (also called goiter)

To control the growth of nodules on the thyroid gland

Treatment after the removal of the thyroid for benign or malignant disease

After treatment of hyperthyroidism by radioactive iodine ablation

How is thyroid hormone replacement therapy dosage determined?

Healthcare providers do careful blood testing to find the proper dose of hormone replacement
therapy for each person. The blood tests reveal levels of thyroid hormones in the
blood, as well as thyroid-stimulating hormone (TSH) released by the pituitary gland.
The pituitary gland plays an integral role in the functioning of the thyroid gland.
It controls how much thyroid hormone is released by making TSH that "stimulates" the
thyroid. Increased levels of TSH may indicate that you have an underactive thyroid
or that thyroid hormone replacement needs to be increased.

You will have lab tests to measure levels of thyroid hormones and TSH. Hypothyroidism
can be a progressive disease. This needs dosage increases over time.

To make sure that your thyroid hormone replacement works properly, consider the following
recommendations:

Maintain regular visits to your healthcare provider.

Take your thyroid medicine at least 1 hour before breakfast and any calcium or iron
medicines you may take. Or take at bedtime, or at least 3 hours after eating or taking
any calcium or iron medicines.

Tell your healthcare provider of your thyroid hormone treatment before beginning treatment
for any other disease. Some treatments for other conditions or diseases can affect
the dosage of thyroid hormone therapy.